National Weather Service Mobile-Pensacola

 

Tropical Storm Lee 2011 Drenches the Northern Gulf Coast

Introduction

Tropical Storm Lee
Tropical Cyclone EvolutionTropical Storm Lee began as a deep convective cloud mass associated with a tropical wave in the Caribbean Sea during the last week of August. By the evening of Thursday, 1 Sep 2011, the cloud mass further developed into Tropical Depression 13 (not shown). By 1 PM the following Friday afternoon (2 Sep), Tropical Depression Lee had formed (see Fig 1b in the table below). Lee gradually churned northward exceedingly slow towards south central Louisiana coast line by Saturday afternoon 3 September, while continuing to produce extremely heavy rainfall over portions of southern Louisiana, southern Mississippi, southern Alabama and the northwest Florida Panhandle (see Fig 1e). The menacing outer rainbands of Lee began dumping near continuous heavy rainfall over portions of southern Alabama, southeastern Mississippi and the northwestern Florida Panhandle by early Saturday morning and that endured through early Sunday before dry air wrapped into Lee’s west side (see Fig 2c). The center of Lee moved over land around sunrise Sunday, 4 September (see Fig 1i). However, it would be a while before Lee would weaken to a depression because it remained nearly stationary while the southern half of the circulation was over water where it could continue to derive additional energy from the warm ocean. The next day, Lee was eventually picked up by an upper air trough, turned northeastward and resumed a faster forward speed late in the day on Sunday (4 September) as it began its welcome exit to the northeast (late Sunday through late Monday – see Figures 1l-o in the Table 1 below).
Lee’s impacts were far reaching across our region. Although the continuous rains became somewhat intermittent as dry air wrapped into Lee from the west, this created a situation from Sunday afternoon through midday Monday whereby individual thunderstorms became more intense due to increasing levels of atmospheric instability. Stronger thunderstorms and associated tornadoes plagued the North Central Gulf Coast Region, as they formed within the detached outer spiral rainbands well to the east of Lee’s center on Sunday and finally to the southeast on Monday. The highest total tide levels (astronomical plus surge effects) ranged from approximately 3.5 to just barely over 5 feet (see Table 4 below).

Lee would give a final blow to our region, literally. While Lee was in the process of being picked up by a fast moving upper air trough, a series of squall lines that produced moderately widespread thunderstorm wind damage along and ahead of the surface cold front, as well as more isolated tornadoes, besieged the area through late Monday afternoon (see the NWS’s Storm Prediction Center’s Daily Storm Reports in Table 3 below). In all, some 10-15 inches of rain fell along coastal sections of Alabama and northwest Florida. Additionally, several weak tornadoes occurred producing modest structural and tree damage. There was also moderate beach erosion and the rip currents endured over a multi-day period. Inland flooding was exacerbated along the immediate coastal zone by higher tide levels due to Lee’s surge effects which created poor to no drainage of area coastal rivers, bays and sounds on during astronomical high tide cycles from 3-5 September (late night hours each day). More specific details, including meteorological and tide gage observations are given in the sections below.

 

Table 1 – Six hour analyses of the evolution of Tropical Storm Lee from 7 PM 1 Sep through 1 AM 6 Sep 2011 (courtesy NWS Hydrometeorological Prediction Center).

12z 9/2/11 Surface Analysis
Figure 1a

18z 9/2/11 Surface Analysis
Figure 1b

0z 9/3/11 Surface Analysis
Figure 1c

6z 9/3/11 Surface Analysis
Figure 1d

12z 9/3/11 Surface Analysis
Figure 1e

18z 9/3/11 Surface Analysis
Figure 1f

0z 9/4/11 Surface Analysis
Figure 1g

6z 9/4/11 Surface Analysis
Figure 1h

12z 9/4/11 Surface Analysis
Figure 1i

18z 9/4/11 Surface Analysis
Figure 1j

0z 9/5/11 Surface Analysis
Figure 1k

6z 9/5/11 Surface Analysis 
Figure 1l

12z 9/5/11 Surface Analysis
Figure 1m
15z 9/5/11 Surface Analysis
Figure 1n
0z 9/6/11 Surface Analysis
Figure 1o
 

 

IMPACTS – Flooding Rainfall

Table 2a – Radar estimated 24 hour (Figs. 2a-2e) and event rainfall totals (Fig. 2f) associated with Tropical Storm Lee. The 24 h totals are given from 2-6 Sep 2011. 

9/2 rainfall ending 12z
Figure 2a

9/3 rainfall ending 12z
Figure 2b

9/4 rainfall ending 12z
Figure 2c

9/5 rainfall ending 12z
Figure 2d

9/6 rainfall ending 12z
Figure 2e

7 day regional observed precipitation valid 9/6/2011
Figure 2f

 
Table 2b – Local rainfall amounts (in.) in descending order associated with Tropical Storm Lee. These are event totals 6 in. and above from 2-6 Sep ending 7 AM CDT 6 September 2011.
Location Event Total Rainfall Amount (in.) Source
Mobile 10.2 WSW 12.62 CoCoRaHS
Tillmans Corner 4.3 WNW 12.17 CoCoRaHS
Robertsdale, AL 11.82 NWS COOP
Grand Bay 0.6 NW 11.70 CoCoRaHS
Theodore 3.7 WNW 11.58 CoCoRaHS
Mobile 11.4 WSW 11.30 CoCoRaHS
Mobile, AL, Bates Field 11.30 NWS
Coden, AL 11.25 NWS COOP
Milton 1.4 NNE 11.04 CoCoRaHS
Mobile, AL (KMOB) 10.94 ASOS
Orange Beach 3.0 ENE 10.83 CoCoRaHS
Mobile 5.7 WSW 10.68 CoCoRaHS
Mobile 0.2 N 10.61 CoCoRaHS
Foley 7.4 SW 10.60 CoCoRaHS
Foley 2.0 SSW 10.56 CoCoRaHS
Mobile 7.4 W 10.56 CoCoRaHS
Elberta 3.1 SSW 10.39 CoCoRaHS
Orange Beach 2.1 NE 10.26 CoCoRaHS
Foley 6.2 SW 10.22 CoCoRaHS
Foley 0.5 ESE 10.21 CoCoRaHS
Mobile 2.6 WNW 9.92 CoCoRaHS
Black Creek, MS 9.88 River Gage
Wilmer 7.9 SE 9.54 CoCoRaHS
Orange Beach 1.3 E 9.50 CoCoRaHS
Wiggins 5.8 E 9.34 CoCoRaHS
Mobile 1.2 WSW 9.18 CoCoRaHS
Wiggins 5.5 ENE 9.17 CoCoRaHS
Perkinston 1.7 NE 9.00 CoCoRaHS
Mobile 4.7 W 8.99 CoCoRaHS
Mobile 1.8 W 8.91 CoCoRaHS
Crestview 2.8 NNW 8.82 CoCoRaHS
Whiting Field, FL (KNSE) 8.72 ASOS
Point Clear 1.6 SSW 8.71 CoCoRaHS
Mobile 5.1 S 8.49 CoCoRaHS
Milligan, FL 8.47 River Gage
Mobile 4.4 WNW 8.42 CoCoRaHS
Theodore 6.7 SSE 8.42 CoCoRaHS
Loxley 0.4 SSW 8.23 CoCoRaHS
Saraland 1.4 E 8.19 CoCoRaHS
Grand Bay 3.1 NNE 8.15 CoCoRaHS
Theodore 8.0 SSE 8.08 CoCoRaHS
Fairhope 0.9 N 7.99 CoCoRaHS
Wiggins, MS 7.93 NWS COOP
Navarre 2.1 WNW 7.91 CoCoRaHS
Crestview 2.5 SSW 7.91 CoCoRaHS
Navarre 2.3 NNW 7.86 CoCoRaHS
Leakesville, MS 3NW 7.84 River Gage
Milton 10.9 SSW 7.82 CoCoRaHS
Milton, FL 7.77 River Gage
Niceville 4.5 SE 7.75 CoCoRaHS
Fairhope 1.5 WSW 7.73 CoCoRaHS
Fairhope 2.3 E 7.72 CoCoRaHS
Fairhope 2.3 N 7.59 CoCoRaHS
Melvin, AL 7.40 River Gage
Lucedale 13.1 SE 7.38 CoCoRaHS
Fairhope 3.1 NNW 7.29 CoCoRaHS
Niceville 5.6 SE 7.26 CoCoRaHS
Waynesboro, MS 7.24 NWS COOP
Pensacola 4.8 N 7.18 CoCoRaHS
Gulf Breeze 7.9 ENE 7.18 CoCoRaHS
Dauphin Island, AL 7.17 NWS COOP
Fairhope, AL 7.13 NWS COOP
West Pensacola 10.9 SW 7.12 CoCoRaHS
Niceville 3.4 ESE 7.11 CoCoRaHS
Fairhope 3.7 NNW 7.05 CoCoRaHS
Niceville 2.3 SE 6.99 CoCoRaHS
Baker 8.2 NE 6.98 CoCoRaHS
McLain, MS 6.92 River Gage
Niceville 3.6 SE 6.90 CoCoRaHS
Milton 17.7 NNE 6.88 CoCoRaHS
Daphne 0.4 SW 6.75 CoCoRaHS
Pensacola 3.8 N 6.75 CoCoRaHS
Toxey 6.0 N 6.68 CoCoRaHS
Leakesville, MS 6.67 NWS COOP
Daphne 4.2 NE 6.65 CoCoRaHS
Pensacola ECUA 6.54 NWS COOP
Eglin Afb 5.6 NE 6.51 CoCoRaHS
Jackson, AL 6.43 NWS COOP
Daphne 1.8 ESE 6.41 CoCoRaHS
Gonzalez 2.5 NNW 6.40 CoCoRaHS
Hurlbert Field, FL (KHRT) 6.40 ASOS
Silverhill, AL 6.39 River Gage
Pace 2.4 N 6.37 CoCoRaHS
Open Pond, AL 6.33 River Gage
Crestview 1.9 SE 6.27 CoCoRaHS
Destin, FL (KDTS) 6.27 ASOS
Spanish Fort 1.2 NE 6.24 CoCoRaHS
Destin 1.0 E 6.23 CoCoRaHS
Daphne 1.2 NNW 6.21 CoCoRaHS
Ensley 2.1 ENE 6.13 CoCoRaHS
Ocean City 1.3 NNW 6.09 CoCoRaHS
Saraland 6.8 NNW 6.06 CoCoRaHS
Shalimar 1.0 N 6.04 CoCoRaHS


IMPACTS- Tornadoes

Individual conformed tornado paths associated with Tropical Storm Lee from 2-6 Sep will eventually be plotted in the NWS Mobile, AL Tornado Museum (found at http://www.srh.noaa.gov/mob/?n=tornado_museum).

Table 3 – 24 h Preliminary Storm Reports from 2-5 Sep 2011 (courtesy NWS Storm Prediction Center). Tornado reports are in red in each of the figures below. Damaging severe thunderstorm wind reports are in blue.

9/2/11 storm reports
Figure 3a

9/3/11 storm reports
Figure 3b

9/4/11 storm reports
Figure 3c

9/5/11 storm reports
Figure 3d

 Composite of known tornadoes associated with Tropical Storm Lee
Figure 3e - Composite of known tornadoes associated with Tropical Storm Lee
Click to Enlarge

IMPACTS – Storm Surge
Table 4 – Event area tide gage observations versus astronomical tidal predictions (referenced to MLLW, mean lower low water). The images progress from west (Fig. 4a) to east (Fig. 4i) geographically.

9/2 to 9/5 Tide observation vs prediction for West Fowl River Bridge
Figure 4a

9/2 to 9/5 Tide observation vs prediction for Dauphin Island
Figure 4b

9/2 to 9/5 Tide observation vs prediction for East Fowl River Bridge
Figure 4c

9/2 to 9/5 Tide observation vs prediction for Dog River Bridge
Figure 4d

9/2 to 9/5 Tide observation vs prediction for Coast Guard Sector Mobile
Figure 4e

9/2 to 9/5 Tide observation vs prediction for Mobile State Docks, AL
Figure 4f

9/2 to 9/5 Tide observation vs prediction for Weeks Bay, AL
Figure 4g

9/2 to 9/5 Tide observation vs prediction for Pensacola, FL
Figure 4h

9/2 to 9/6 Tide observation vs prediction for Panama City, FL
Figure 4i

 

IMPACTS – Peak Sustained Wind Speeds and Gusts
Tropical Storm Lee produced the following peak wind 10 m speeds (Table 5 below).
Table 5 – Peak 10 m sustained 2 min wind and gust data. Sustained wind speeds are assumed to be 2 min unless otherwise specified. Directions are given in whole degrees. The data are presented in descending order according to the peak wind gust. If data are missing, they are not currently available.
Location
Peak 10 m Wind Gust (mph) and Direction (deg)
Date and Time (CST)
Peak 2 min Sustained Wind (mph) and Direction (deg)
Date and Time (CST)
Hurlburt Field, FL at runway 36 /FMQ-19/ sensor 65 5/1031    
AL DOT I-10 Bayway Exit 30 65 5/0725    
Duke Field, FL (KEGI) ASOS 63 5/1424    
Dauphin Island,AL C-MAN (DPIA1) 63 from 180° 5/0928 40 from 170° 5/0854
Pensacola ,FL Regional (KPNS) ASOS 59 from 200° 5/1047 43 from 190° 5/1047
Destin, FL (KDTS) ASOS 59 from 200° 5/1136 32 from 180° 5/1216
Mobile, AL Brookley Field, (KBFM) ASOS 55 from 320° 5/1542 41 from 320° 5/1543
Ensley, FL - Trained storm spotter (public report) 55 5/1201    
Hurlburt Field, FL (KHRT) ASOS 55 5/1033    
Brent, FL - Trained storm spotter (public report) 53 5/1149    
NAS Pensacola, FL (KNPA) ASOS 53 from 210° 5/1140 37 from 200° 5/1256
Mobile, AL Regional (KMOB) ASOS 48 from 200° 5/0703 35 from 200° 5/0701
Crestview Sikes,FL (KCEW) ASOS 46 from 200° 5/1349 31 from 190° 5/1349
Location
Peak 10 m Wind Gust (kt) and Direction (deg)
Date and Time (CST)
Peak 2 min Sustained Wind (kt) and Direction (deg)
Date and Time (CST)
Dauphin Island (USA Mesonet) 44 from 200° 5/0816 48 from 190° 5/0813
Fairhope, AL (USA Mesonet) 36 from 330° 5/1658 37 from 320° 5/1657
Jay, FL (USA Mesonet) 36 from 190° 5/1317 49 from 185° 5/1316
Elberta, AL (USA Mesonet) 33 from 170° 5/0529 39 from 180° 5/1021
Grand Bay, AL (USA Mesonet) 32 from 190° 5/0744 37 from 130° 5/1712
Walnut Hill, FL (USA Mesonet) 32 from 175° 5/1311 42 from 170° 5/1309
Andalusia, AL (USA Mesonet) 30 from 210° 5/1213 37 from 200° 5/1127
Loxley, AL (USA Mesonet) 31 from 170° 5/1312 38 from 170° 5/1319
Robertsdale, AL (USA Mesonet) 31 from 110° 3/1604 37 from 180° 5/1128

Disclaimer: These data are being updated as newer information becomes available. The NWS in Mobile, AL reserves the right to modify these data anytime based on the latest available and highest quality data.

Acknowledgements – This was page was authored by Jeffrey Medlin (Science and Operations Officer) and Ray Ball (Information Technology Officer) with contributions from Kirk Caceres (Forecaster), Jason Beaman (Lead Forecaster), Jeff Garmon (Warning Coordination Meteorologist), Gene Jacobi (Observing Program Leader), Joe Maniscalco (Forecaster), and John Werner (Meteorological Intern).


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